Структура и динамика полярных токовых систем : материалы международного симпозиума «Полярные геомагнитные явления», 25-31 мая, Суздаль, СССР / Акад. наук СССР, Кол. фил. им. С. М. Кирова, Поляр. геофиз. ин-т. – Апатиты : [б. и.], 1988.

- existence of a toroidal, magnetic field within the ionosphere in the equatorial region on the dusk side, caused by an upward electric current above the dip equator and its associated current circulation in the meridional plane; and - global antisunward net current of a few million Amperes flowing below the MAGSAT level during the developing stage of magnetio storms. The magnetic field measurements by many previous satellites have contri buted to the demonstration of the field configuration around the earth, espe cially its quantitative deviation from a dipole magnetic field. Magnetometers on board of synchronous-orbit satellites showed a sudden transition from a tail-like magnetic field to a dipolar configuration near the midnight meridi an at the onset of magnetic substorms, whioh is associated with a disruption of westward tail current, i.e. its conversion into the ionospheric current connected with a pair of field-aligned currents in the magnetosphere. Electric fields and currents in the vicinity of an auroral arc. Rinnert K. and Kohl H. - Вкн.: Структураидинамикаполярныхтоковыхсистем. Апатиты, изд. КольскогофилиалаАНСССР, 1987, о. 89-95. Electric field measurements from dc to 150 Hz were performed on board the CAESAR payload which flew over a faint auroral arc just below its apogee at 703 km. The CAESAR dc-electric field together with electric fields derived from EISCAT measurements in 140 km altitude defined an electric field and current configuration associated with a local perturbation, Equatorward of the precipitation region (inverted-V-event) intense electrostatic low freque ncy noise was observed. These signals had properties of electrostatic ion cyclotron (EIC) waves. As their electric field was predominantly polarized parallel to the Earth magnetic field, these waves are attributed to ion beam driven modes. The spatiality or temporarity limited occurence of the fluctua tions gives an indication of the structure of the beams or field-aligned current system. Effects of sudden impulses (SI) and aubstorms on Pel magnetic pulsation spectrum, Kangas J., Aikio A., Pikkarainen T-, Parmer A,, Olson J.V,, Turunen Т. - Вкн.: Структураидинамикаполярныхтоковыхсистем. Апати ты, изд. КольскогофилиалаАНСССР, с. 95-101. We present some examples of magnetic pulsation spectra measured at the north-south chain of pulsation magnetometers in Finland where the ongoing Pel wave activity is interrupted by a sudden impulse or magnetospheric substorm. We show that Si's induce most prominent changes in the Pel spectrum at auro ral latitudes. This is shown to be mostly in agreement with model calculati ons where the growth rate of ion-cyclotron waves ia changed by an increase in the ambient magnetic field and in anisotropy of the plasma pressure. The sub storm onset induces an upward sweep of Pel frequency and a typical IPDP pulsa tion event is observed. We show that this is associated with an enhanced southward drift of plasma measured by the EISCAT radar. We conclude that the increase in frequency is due to the j x l drift of the wave source in the magnetosphere. I47